Power Management GL431

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Myrtle Burns
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1 Description The is a three terminal adjustable shunt regulator with thermal stability guaranteed over temperature. Output voltage can be adjusted to any value between.5v (V ) and 36V by using two external resistors. The has a typical dynamic output impedance of 0. ohm. Active output circuitry provides a very unique turn on characteristic, making the an excellent replacement for zener diodes in many applications such as onboard regulation and adjustable power supplies. The is an ideal voltage erence for 3.0 to 3.3V switching power supplies. Features Sink Current Capability 1 ma to 100mA Low dynamic output impedance, 0. ohm typ. Low output noise 0.5% or 1% erence voltage tolerance Alternate for TL431, TL431, LM431 & AS431 Temperature range 0 C to +70 C Available in SOT-3 and TO-9 packages The shunt regulator is available with 3 voltage tolerances 0.5% and 1.0% over T A =0 C to +70 C, and four package options (SOT-3 and TO-9).Whatever your application is, the offers the optimum combination of performance, reliability, and economy. Application Switching power supplies Linear regulators Adjustable supplies Battery-operated computers Computer disk drives Instrumentation LOGIC SYMBOL BLOCK DIAGRAM (POSITIVE LOGIC) CATHODE ANODE REFERENCE CATHODE REFERENCE + _ ANODE V1. 1

2 MARKING INFORMATION & PIN CONFIGURATIONS (TOP VIEW) TO- 9 GL 431G AYYWW SOT-3 Anode 3 XXXYYW 1. REF. Anode 3. Cathode 1 REF Cathode 1 3 XXX = Marking Code G** = Grade A = Assembly Location YY = Year WW,W=Weekly ORDERING INFORMATION (Green Package Products are available now!) Ordering Number Precision Device code Grade Package Shipping AT9B 0.5% A TO-9 1,000 Units/ ESD Bag AT9RL 0.5% A TO-9,000 Units/ Ammo Pack(Tape) AST3R 0.5% AAA SOT-3 3,000 Units/ Tape &Reel BT9B 1% B TO-9 1,000 Units/ ESD Bag BT9RL 1% B TO-9,000 Units/ Ammo Pack(Tape) BST3R 1% AAB SOT-3 3,000 Units/ Tape &Reel * For detail ordering number identification, please see last page. ** Grade A: indicates Precision of 0.5%, B: indicates Precision of 1%

3 EQUIVALENT SCHEMATIC CATHODE REF 0pF K 4K.4K 7.K 0pF 10k 1k ANODE 800 * All component values are nominal. Pin numbers shown are for the D package. 3

4 ABSOLUTE MAXIMUM RATINGS (over free-air temperature range except as noted) PARAMETER SYMBOL Value UNIT Cathode Voltage (1) V KA 37 V Continuous cathode current range I K -100 to 150 ma Reference input current range I -50 μa to 10mA ma Power dissipation at T A =5 C SOT-3 TO-9 Package thermal impedance SOT-3 TO-9 (, 3) P D JA W C/ W Operating ambient temperature range T A 0to+70 C Lead temperature (soldering) 10 seconds T LEAD 60 C These are stress ratings only. Functional operation of the device at these or any conditions beyond the "recommended operating conditions" is not implied. Exposure to absolute maximum rated conditions may affect device reliability. NOTES: 1. Voltage values are with respect to the anode except as noted.. Maximum power dissipation is a function of T J(max), JA and T A. Maximum allowable power dissipation at any allowable ambient temperature is P D = (TJ(max) - T A)/ JA. 3. Package thermal impedance is calculated per JESD 51. RECOMMENDED OPERATING CONDITIONS PARAMETER SYMBOL MINIMUM MAXIMUM UNIT Cathode Voltage V KA 36 V Cathode Current I K ma 4

5 ELECTRICAL CHARACTERISTICS (T A = 5 C unless otherwise noted) A (0.5%) PARAMETER CONDITION MIN TYP MAX UNIT (1) V =V I =10mA T =5C Reference Voltage V KA, K, A V KA=V, I K =10mA, T A =0to70C (1) V (1) V temp deviation V dev V KA =, I K = 10 ma, T A = full range 4 17 mv Ratio of change in V V V KA = 10V to V I K = 10mA mv/v to change in V -0.4 KA VKA V KA = 36V to 10V -.0 Reference input current I I K = 10mA, R1 = 10K, R = Deviation of erence I input current over full I K = 10mA, R1 = 10K, R = (dev) temperature range T A = full range () () A A Minimum operating current I K(min) V KA= V (1) ma Off-state cathode current (3) V KA =36V, =0V I K(off) (3) V KA =16V, =0V Dynamic impedance Z KA f 1kHz,V KA=, I K=1mA to 100mA (1) A B (1.0%) PARAMETER CONDITION MIN TYP MAX UNIT (1) V =V I =10mA T =5C Reference Voltage V KA, K, A V KA=V, I K =10mA, T A =0to70C (1) (1) V temp deviation V dev V KA =, I K = 10 ma, T A = full range Ratio of change in V V V KA = 10V to V I K = 10mA to change in VKA VKA V KA = 36V to 10V () Reference input current I I K = 10mA, R1 = 10K, R = Deviation of erence () I = 10mA, R1 = 10K, R = I K input current over full (dev) temperature range T A = full range V mv mv/v A A Minimum operating current I K(min) V KA = V (1) ma Off-state cathode current NOTES: (1) See test circuit 1 on page 6. () See test circuit on page 6. (3) See test circuit 3 on page 6. (3) V KA =36V, =0V I K(off) (3) V KA =16V, =0V Dynamic impedance Z KA f 1kHz,V KA=, I K=1mA to 100mA (1) A

6 TEST CIRCUITS V IN V KA V IN V KA V IN V KA l k R1 l l (off) k l R Test Circuit 1 V = V KA Test Circuit V > V KA Test Circuit 3 Off-State 6

7 TYPICAL APPLICATIONS A, B V out V out V out =( ۱+ ) Figure 1. Shunt Regulator V out =( ۱+ ) Figure. High Current Shunt Regulator 7805 In Out Common V out V out V out =( ۱+ ) V out(min) = + 5.0V Figure 3. Output Control for a Three Terminal Fixed Regulator V out =( ۱+ ) V out(min) = + V be.0v Figure 4. Series Pass Regulator R CL I out Vout I sink I sink = R S I out = R CL R S Figure 5. Constant Current Source Figure 6. Constant Current Sink V out V out V out(trip) =( ۱+ ) Figure 7. TRIAC Crowbar V out(trip) =( ۱+ ) V Figure 8. SCR Crowbar 7

8 Typical Performance Characteristics Cathode current ( A) Cathode current (ma) Cathode Voltage (V) Figure 9. Cathode Current vs. Cathode Voltage Cathode Voltage (V) Figure 10. Cathode Current vs. Cathode Voltage I, REFERENCE INPUT CURRENT (ma) TA, AMBIENT TEMPERATURE ( C) Figure 11. Reference Input Current versus Ambient Temperature Impedance ( ) K 00K 300K 400K 500K 600K Frequency (Hz) Figure 1. Dynamic Impedance Frequency V, REFERENCE INPUT VOLTAGE (V) TA AMBIENT TEMPERATURE Figure 13. Reference Input Voltage versus Ambient Temperature A, OPEN LOOP VOLTAGE GAIN (db) vol k 10k 100k 1M f, FREQUENCY (HZ) I K=10mA T A=5 C Figure 14. Open-Loop Voltage Gain vs. Frequency Phase Shift 8

9 Design Guide for AC-DCSMPS (Switching Mode Power Supply) Use of Shunt Regulator in Transformer Secondary side Control This example is applicable to both forward transformers and flyback transformers. A shunt regulator is used on the secondary side as an error amplifier, and feedback to the primary side is provided via a photocoupler. Transformer R 1 384X 38C4X SBD I F R 3 (+) Output V F I B R V O (-) Phototransistor Photocoupler Light emitting diode V K C 1 R 5 V REF R 4 GND Figure 16. Typical Shunt Regulator/ Error Amplifier Determination of External Costants for the Shunt Regulator Dc characteristic determination: Next, the output voltage can be determined by R3 In figure 16, R1and Rare protection resistor for and R 4, and the following formula is obtained: the light emitting diode in the photocoupler, and R is a bypass resistor to feed IK Minimum, and these R3 +R4 V O = XV,V erf =.5VTyp are determined as shown below. The photocoupler R4 specification should be obtained separately from the manufacturer. Using the parameters in figure 16, the The absolute values of R3 and R4 are determined following formulas are obtained: by the erence input current I and the AC characteristics described in the next section. VO - VF- VK VF R1 =, R = The I value is around 0.7A Typ. I +I I F B B VK Is the operating voltage, and is set at around 3V, taking into account a margin for fluctuation. R is the current shunt resistance for the light emitting diode, in which a bias current IB of around 1/5 I flows. F 9

10 AC Characteristic Determination: This ers to the determination of the gain frequency characteristic of the shunt regulator as an error amplifier. Taking the configuration in figure 16, the error amplifier characteristic is as shown in figure 17. G1 Gain G (db) * f osc : PWM switching frequency When R 5= 0 G When R 5= 0 F1 F AC F Fosc Frequency f (Hz) Figure 17. Error Amplification Characteristic In Figure 17, the following formulas are obtained: Gain G 1= G0 50 db to 60 db (determined by shunt regulator) R5 G = R3 Corner frequencies f 1= 1/( C1G0R 3) f = 1/( C1R 5) G0 is the shunt regulator open-loop gain; this is given by the reciprocal of the erence voltage fluctuation V/ V KA, and is approximately 50 db. Practical Example Consider the example of a photocoupler, with an internal light emitting diode V F= = 1.05 V and I F =.5 ma, power supply output voltage V = 5 V, and bias resistance R current of approximately 1/5 IF at 0.5 ma. If the shunt regulator V = 3 V, the following values are found. K 5V V - 3V R 1= =316.5mA + 0.5mA 1.05V R = =.1 k 0.5mA Next, assume that R 3 = R 4 = 10 k. This gives a5voutput. If R 5 = 3.3 k and C 1 = 0.0 μf, the following values are found. G = 3.3 k / 10 k = 0.33 times ( 10 db) f 1 =1/(x x0.0 μf x 316 x 10 k ) =.3 (Hz) f =1/(x x0.0 μf x 3.3 k ) =. (khz) 10

11 S SOT-3 PACKAGE OUTLINE DIMENSIONS ± REF 0.45 ± ± ± BSC 1.90 BSC ~ ± ± ± ± 0.05 Unit: mm D TO-9 PACKAGE OUTLINE DIMENSIONS ±0. 10 Φ ± ± ± ( max) ± ± ± ± Unit: mm 11

12 ORDERING NUMBER A T9 B Circuit Type Voltage Tolerance A: 0.5% B: 1.0% Shipping B : EDS Bag RL: Ammo Pack (Tape) R: Tape & Reel T: Tube Package T9: TO-9 ST3: SOT-3 1

AT431 Adjustable Precision Shunt Regulators

AT431 Adjustable Precision Shunt Regulators FEATURES DESCRIPTION Programmable Output Voltage to 40V Voltage Reference Tolerance 1.0% for B Series and 0.5% for A Series Low Dynamic Output Impedance 0.22Ω Sink Current Capability of 0.1mA to 100mA